Get an Energy audit first before you do all these, you may qualify for upgrade grants.This will also prioritize your upgrades if you are on a budget. Windows and doors may be lower on the list than you think.
Buy or borrow an LED or infra red heat detecting laser gun and scan your walls, windows and corners floor to ceiling. You will find cold pockets in many locations.
I found 7-10 degree variation and my home would be considered a well built custom home, but it is 35 years old.
Buy foil tape and seal your heat ducts at all visible joints. 3 screws per joint is code so they don`t sag open. You could consider wrapping exposed ducting with insulation.
New low flush toilets move 2-3 times the volume of waste as those made 8 years ago with the same flush rate. There is an actual web site for toilet comparisons.
Before insulating your attic check to see it has the proper balance of soffit to rooftop ventilation and seal gaps for plumbing and wiring. There is a correct ratio required to help eliminate heat buildup which radiates down into the home, making the top floor hot. Insulation alone will not cure the heat issue. Egg crate type joist liners are availble for the underside of the roof to help channel heat up and out the vents at rooftop.They should be installed before extra insulation is added
Buy foam seal kits for switches and receptacles on all outer walls , but on the top floor walls do both inner and outer walls as they can draft from the attic above.
Check to ensure bath fans have a functioning damper
in place and are vented to the outside of the home, not the attic. Remove your fan grills and check for leakage around the cutouts in the dywall. Consider installing timers on your bath fans.
Replace outside dryer, bath fan and range vents with one with a weighted steel damper or styrofoam ball trap. This prevents back draft or sticking vent doors. I used the steel type with an extra washer for weight on the door. My basement and kitchen are noticeably warmer in winter since this one upgrade.
Unless you can see tyvek type wrap and sealant on the insideand underside of the sill , insulating and sealing
the rim joist and sill plate in the basement to R23 or better has a huge effect, second in savings only to a high efficiency furnace. Use expansion foam above and below the sill plate and any penetrations for the entire perimiter...Use window foam at all windows and doors throughout the house, basement inciuded. You may consier removing door casings in an older home, pulling pout the fiberglass and sealing with foam.
Since completing the sill plate and rim joist my heat bill is down over 35% in consumption with the new furnace and I have yet to complete the actual basement walls... I was told by a heating contractor up to 15% of heat is lost through draft in the rim joist area.
Insulate basement walls floor to ceiling. Spray foam is becoming popular, but read up on the chemical makeup and fire hazard due to fumes if burned. Natural plant based foam sprays are emerging....I`m still looking for a green option with less off gasing.
Run a bead of sealant around the entire structure under the outside wall baseboards especially if the house is 10 years old or more. Peel back carpeting and run the bead right at the wall. Latex foam works well and cleans up easy. Pay extra attention to closets and corners.
Install a waste water recovery system. It will capture and preheated drain water energy and reduce water heater load. While you`re at it check the age and efficiencey of your water heater and water softener.
A Bosch dishwasher contains it`s own heating element for wash and rinse water, which then evaporates, eliminating an exposed hoop element for drying...I am told it uses less water as well.
Check lower corners of your entry doors for draft. Install corner seals at both corners. Caution, installing these will change the level and closure of the door...
New front loading clothes washers use far less water than conventional style. LG and Samsung are among last years better rated ones as far as quality.
Anybody else..... Lets keep this rolling, this should be a forum.